1. Field of Invention
This invention relates generally to adjusting the length of a pipe, and more particularly, to an apparatus and method for adjusting the height of a sprinkler head riser.
2. Description of Related Art
In golf courses, lawns and other grass covered areas, frequent watering is required to maintain the area in an esthetically pleasing and healthy condition. It is well known in the art that a network of distributed pipes and sprinkler head attachments may be provided underneath the surface of the ground to provide the required watering. Such an underground system is not visible when not in use, and does not require set up for each watering, but merely requires activation.
In the field of golf course design, in-ground sprinkler heads and their associated network of piping are common. The use of in-ground sprinkler systems in golf courses, however, presents unique design requirements due to the nature of the game of golf which is played around such sprinkler heads.
Firstly, the top surface of the sprinkler head is required to be as level with the surround ground as possible. Should the sprinkler head extend above the surface of the surrounding ground, it may pose a hindrance or obstruction to any golf ball which may come into contact or close proximity to the sprinkler head. Conversely, should the sprinkler head be at a position below the surface of the surrounding ground, the sprinkler head may create a depression in the playing surface of the golf course with the result that golf balls tend to roll into such a depression. Therefore, should the top surface of the sprinkler head assembly not be flush with the surrounding ground, the sprinkler may serve to reduce the enjoyment of the golf players, due to the above-mentioned hindrances, thereby reducing the desirability of the course.
Secondly, a frequent activity of golf course maintenance is to distribute sand or other soil material across the top surface of the golf course. This addition of soil to the golf course may serve to reduce the height of the top surface of the sprinkler head relative to the surrounding ground as the additional soil is added. Therefore, it is frequently necessary to increase the height of the sprinkler head relative to the distribution piping network so as to maintain the top surface of the sprinkler head flush with the surrounding ground. In the past, this activity has required excavation of the sprinklers so as to adjust the height of the sprinkler head relative to the water supply lines. This is commonly accomplished by adjusting the angle of a conventional swing joint. It will be appreciated that such an activity of excavating and adjusting the height of each individual sprinkler head on a golf course is a time consuming and expensive activity. This periodic excavation of the sprinkler heads, also serves to render the immediate vicinity around the sprinkler head unplayable for a certain period of time while the necessary adjustments are being made.
In addition, any grassy surface such as a golf course is required to be cut periodically through the use of a mower. On a property such as a golf course, such a mower is a large piece of equipment having a substantial weight. During the process of mowing the golf course, the wheels of such a mower may ride over top of a sprinkler in the ground. This will transfer the large weight of mower to the sprinkler head and any equipment under it for a short period of time.
Therefore, any structure applied under a sprinkler head assembly will be required to be strong and flexible enough so as to receive the weight of the machinery on the top surface without breaking the underlying piping structure or causing a leak which would be required to be excavated and repaired. The apparatus should also allow for the sprinkler head to accept the weight of the mower on the top surface and still return the sprinkler head to a position flush with the surrounding ground.
Several attempts have been made to supply a sprinkler head riser having adjustable length so as to allow the height of the sprinkler head to be readily adjusted. All previous attempts to solve this problem have resulted in defects that have limited their acceptance. Many of these attempts still require the sprinkler head riser assembly to be excavated to access the adjusting means which is buried.
In addition, many previous attempts have relied upon threading or ridges between a pair of telescoping bodies. These attempts have relied on a fixed structure to extend the riser assembly and resist the compressive forces of the mower. Disadvantageously, such mechanisms may become damaged and jammed should the applied weight of the mower become to great. In addition, such mechanisms have a tendency to become jammed by the inclusion of dirt and other contaminants.
Other previous attempts have relied upon a biasing element securing a connection between two telescoping members. These mechanisms rely on a frictional or non-returning engagement between the biasing element and the telescoping members to secure relative position between them. These mechanisms have the disadvantage of not enabling the height of the sprinkler head to return to a set position after been forcibly compressed, for example, by the weight of a mower.
Finally, attempts have been made to enable a portion of one telescoping member to ride on a spiral spring contained within another telescoping member. These mechanisms have typically included the spring and telescoping apparatus in the stream of water passing through the sprinkler head riser and therefore, are prone to fouling and corrosion from the water and its included minerals.
What is required is a sprinkler head riser apparatus, the height of which may be adjusted without excavation of the apparatus that is able to withstand the weight of a mower placed on the sprinkler head without damage to the apparatus and surrounding piping. It is also desirable that the riser apparatus protects the height adjusting means from fouling from soil or contaminants in the water.